A drain valve of this kind is known through Swedish SE No. 407 615 or its German counterpart DE-OS No. 28 37 080. This drain valve has clear advantages over prior known devices but also under certain circumstances a few disadvantages.
One such disadvantage is that it is impossible to obtain a certain orientation of an electric connector means protruding from the housing; such an orientation is often desired and sometimes even imperative.
Another disadvantage is that a ventilation of the tank through the drain valve, which is necessary at certain service works and before a dismounting of the valve, can only be accomplished in that the valve element is manually lifted somewhat by an object inserted through the outlet.